1. Field of the Invention
The present invention relates to methods of calculating correction values and methods of manufacturing printers provided with motors.
2. Description of the Related Art
Printers are provided with various types of motors, including carriage motors for moving a carriage and carry motors for carrying paper. To control these motors, printers are provided with PID control circuits.
The amount of current that flows through a motor when the motor is driven changes according to the load on that motor. Accordingly, if the value of the current that is flowing through the motor cannot be measured directly, then the output value of an integral element of the PID control circuit is measured, and the value of the current flowing through the motor is calculated based on this output value of the integral element.
Motors have individual differences, however, and thus errors occur when the property values of a standard motor are used to calculate the current value from the output value of the integral element. Accordingly, current values calculated based on the property values of a standard motor are corrected by a correction value (see JP 2003-79172 A).
However, the current value cannot be calculated accurately unless a correction value that is suited for the individual differences of the motor has been set properly.